London: Scientists have developed a new device that works like a `rear-view mirror` for doctors during bowel examinations, helping to detect 25 per cent more cancer cells on average.

The Third Eye Retroscope provides an additional video camera which gives a rear-facing view to reveal the areas behind folds that are hidden from the front-facing view of the colonoscope.

The device developed by US scientists is used along with a standard colonoscope to improve detection, the `Daily Mail` reported.

The device is contained on a J-shaped attachment fixed to the tip of the colonoscope. Studies show having that extra view significantly improves detection rates ? especially among patients at high risk of bowel cancer.

An international study of 395 patients revealed the Third Eye colonoscopy identifies 40 per cent more adenomas in people at high risk of bowel cancer, and 23 per cent more in the general population.

No large adenomas were missed using the new device. For patients, the experience is exactly the same as a traditional colonoscopy.

To look for the early warning signs of bowel cancer, thousands of patients a year undergo a colonoscopy.

This 30-minute out-patient procedure, often carried out under sedation, involves a colonoscope ? a thin, bendy tube with a video camera and light on the end of it ? being inserted into the bowel.

As the device is withdrawn from the body, the camera relays video images of the inside of the bowel back to the doctor to check for abnormal growths, called adenomatous polyps or adenomas ? these can then be removed before they become cancerous.

Earlier research showed that removing adenomas reduces deaths from bowel cancer by 53 per cent, the report said.

However, a number of studies have shown that traditional colonoscopies miss between 21 and 24 per cent of adenomas, and 12 per cent of large adenomas 1cm or more in size which are at greatest risk of becoming cancerous.